Because ‘optimistic bias’ reduces our perception of the risk is the short answer. But let’s start at the beginning.

Pride we can feel in our responses to Monday’s devastating earthquake in north Canterbury. It is gratifying to know that we can handle such catastrophe with efficiency and compassion with the earthquake ambulance being at the bottom of the cliff.

If we could, would we work to avoid these catastrophes, to put the ambulance at the top of the cliff?

The timings and scale of earthquakes are random by nature and an ability to predict them is not realistic. So for earthquakes, ambulances at the top of the cliff are unlikely to benefit us.

Like earthquakes, we know that catastrophic weather events will occur, but not where, nor when they will do so.

Like earthquakes, we know the causes of catastrophic weather events.

But unlike earthquakes, we can do things now to mitigate the risk of catastrophic weather events.

So knowing what is causing them, (scientists have become very good at attributing causes to climate change) why are we not preparing for them?

The answer lies in research prepared for our Earthquake Commission following the 2010-2011 Canterbury quakes.

This research looked at changes in individual preparedness for and judgments of the risk, of earthquakes.

The researchers found that personal experience of a catastrophic earthquake changes people’s perception of the risk of further events, and therefore, their preparation for it.

Where there is a high risk of earthquakes, for example Wellington, people prepare for the risk. Following the Canterbury earthquakes, the risk perception of Wellingtonians did not change – they were already risk-aware.

When there is a perception of a low risk of earthquakes, Palmerston North and pre-2010 Christchurch, people had an optimistic bias that they would not be earthquake victims.

Following the 2010-2011 Canterbury quakes, Palmerston North people lost that optimistic bias, but only for a short time so they did not take mitigation actions.

Because Christchurch people experienced the trauma, they too lost that optimistic bias. For many, their new assessment of the risk of another earthquake has remained with them and as a consequence, they have taken actions to mitigate that risk.

So the lesson from the Canterbury earthquakes is that humans have an optimistic bias of invincibility, and so downplay the risks and under-prepare for catastrophic events. Until one hits them that is.

How can that lesson be applied to catastrophic weather events?

What we have to do is really simple:

reduce our carbon emissions: cut back on the food we waste; Reduce, Reuse, Recycle waste; buy only things we need (and not the bling we want but do not need); drive fewer miles; and reduce electricity consumption.

sequester carbon: bury charcoal to become biochar.

plant trees:

and stop using fossil fuels: drive fewer miles, upgrade to an electric vehicle or a smaller car.